(NEW YORK) -- After his lackluster performance at the first presidential debate, President Obama is making some “adjustments” and will be more “aggressive” in his second face-off with Republican nominee Mitt Romney, senior Obama campaign adviser David Axelrod said Sunday.

“Nobody’s a harsher critic than the president is of himself and he viewed the [debate] tape,” Axelrod said on “Fox News Sunday.” “I think he’s going to make some adjustments on Tuesday.”

Axelrod would not detail any strategic changes that the president might be making, but said he’s “going to be aggressive in making the case for his view of where we should go as a country.”

Appearing on CNN’s “State of the Union,” senior Obama campaign adviser Robert Gibbs said the president was “disappointed” in his performance in Denver.

“He didn’t meet his own expectations,” he said. “He knew when he walked off that stage, and he also knew as he’s watched the tape of that debate, that he’s got to be more energetic. I think you’ll see somebody who is very passionate about the choice that our country faces, and putting that choice in front of voters.”

Expect the president to continue to attack Romney for his changing positions. In the two weeks since the first debate, the president’s campaign has tried to cast the GOP nominee as an extreme conservative trying to reinvent himself as a moderate in the run-up to the election.

Gibbs described Romney’s performance at the first debate as “magical and theatrical” because “for 90 minutes he walked away from a campaign he’d been running for more than six years previous to that.”

“We saw Governor Romney, sort of, serially walk away from his own proposals and certainly the president is going to be willing to challenge him on it as we saw the vice president challenge Paul Ryan,” Axelrod said.

The president is spending the three days leading up to the debate hunkered down with his advisers in Williamsburg, Va., where he is practicing and studying at a luxury resort.